From: "A.Appleyard" <A DOT APPLEYARD AT fs2 DOT mt DOT umist DOT ac DOT uk>
To: DJGPP AT sun DOT soe DOT clarkson DOT edu
Date: Thu, 9 Nov 1995 11:36:40 GMT
Subject: pk(un)zippers

  Hereinafter, `A.ZIP | B' means the (file image stored packed inside zip file
A.ZIP) which is named B in A.ZIP's internal directory.
  All pkzippers and equivalents that I know of, can only read from DOS file
(e.g.) QWERTY into zipped file image ZXCVBNM.ZIP | QWERTY
  Please, is there a pkzipper or equivalent anywhere that will let me copy DOS
file QWERTY into zipped file image ZXCVBNM.ZIP | ASDFGHJ ?

  The same nuisance occurs with pkunzippers, but I can dodge it by typing
    PKUNZIP -c ZXCVBNM.ZIP ASDFGHJ > QWERTY
  and pkunzip tries to copy zipped file image ZXCVBNM | ASDFGHJ to screen, but
`>' catches it and sends it to file QWERTY
  But I can't type this:-
    PKZIP -{some option} ZXCVBNM.ZIP ASDFGHJ < QWERTY
  as PKZIP has no option to read a file from the keyboard (or from wherever
'<' has redirected the input).

  But I would rather be able to copy from ZXCVBNM.ZIP | ASDFGHJ to QWERTY
<and> from QWERTY to ZXCVBNM.ZIP | ASDFGHJ without having to pipe or redirect,
as I want to call the zipper and unzipper from inside another program, and I
would rather call the zipper and unzipper as child processes rather than have
to use system().
  Does calling system() load another copy of COMMAND.COM? What extra load does
calling system() have, over calling a child process?
  Has any trouble been reported when calling (1) ordinary programs, (2) Gnu
C++ programs, as child processes of Gnu C++ programs (a) ordinarily, (b) when
the parent was called in Windows, (c) when particular TSR's or interrupt
hookers (e.g. Novell Netware) are active in the PC?